The DE 10 2009 027 911 A1 describes a vehicle environment monitoring system of this kind, where the signaler generates an audio signal to be perceived outside the vehicle. This conventional monitoring system is proposed for use in electric or hybrid vehicles in order to ensure with the aid of an audio signal that the vehicle cannot approach a pedestrian unnoticed although the noises it makes while being electrically driven are very quiet noises.
Automatic detection of people in the environment of the vehicle is not only useful for warning affected people of a low-noise vehicle approaching but it can also be used, independently of whether the vehicle is an electrically driven vehicle or a vehicle driven by a combustion engine, for drawing the driver's attention to people external to the vehicle which he might have overlooked.
In the vast majority of cases an attentive driver will be automatically aware of people present in the vicinity of the vehicle which might cross its path, whilst a monitoring system generating clues as to the presence of all these people, is a hindrance in that it contributes to sensory overload for the driver rather than increasing safety.
It is therefore the requirement of an embodiment of the present disclosure to propose a vehicle environment monitoring system that can warn the driver of the presence of people in the environment of the vehicle without creating sensory overload.
The requirement is met in that a vehicle environment monitoring system with a people detection unit for detecting the presence of people in the vicinity of the vehicle and with a danger signaler for generating danger signals at least of a first kind, includes a decision unit for deciding on the generation of a danger signal of a first kind when detecting a person by means of the people detection unit in dependence of the visibility of the person for a driver of the vehicle.
By not generating a signal for well visible people the number of signals can be considerably reduced, thereby diminishing the danger of merely irritating the driver through the generation of superfluous signals.
The people detection unit may be adapted, when detecting the presence of people, to distinguish between people in a core warning region and a peripheral warning region surrounding the core warning region, and the danger signaler may be adapted to emit a danger signal of the first kind when a person is present in the peripheral warning region and a danger signal of the second kind when a person is present in the core warning region. In this way it is possible to differentiate between different danger levels originating from people in different warning regions. In particular the core warning region can essentially correspond to the driving path, i.e. the space through which the vehicle will move in extrapolation of its previous course and in which a collision is therefore to be expected if the vehicle maintains this course. The peripheral warning region however can extend on either side of the driving path so that a collision with a person present in it is to be expected only if the person advances into the driving path.
Detection of a person within the core warning region should be sufficient reason for emitting the danger signal of the second kind, whilst detection of a person within the peripheral warning region is merely a necessary reason and a decision is made based on the visibility of the person as to whether a danger signal of the first kind should actually be generated, as described above. The danger signal of the second kind should include an acoustic signal in order to be perceived by the driver independently of his viewing direction.
The danger signal of the first kind is preferably only an optical signal in order to avoid sensory overload for the driver through acoustic signals and in order to avoid that he gets hardened, possibly, against such signals as a result. In order to assess the visibility of a person in the vicinity of the vehicle for the driver the decision unit may be connected with means for detecting the viewing direction of the driver. Means of this kind such as for example a camera directed at the eyes of the driver are known as components of systems for detecting driver fatigue and can, in terms of the monitoring system according to the present disclosure, be adapted at small expense to fulfill this need. If the detected viewing direction of the driver does not coincide with the direction in which the person has been detected, then the person is presumably not visible to the driver and the danger signal should be emitted.
The decision unit can further be connected with a brightness sensor for assessing the visibility of a detected person, in order to take account of the fact that the visibility of people depends upon the brightness of the environment. Rain may also have an influence on how the driver perceives the vehicle environment. Therefore the decision unit for assessing the visibility of the detected person is conveniently also connected with a rain sensor.
It is also advantageous if the decision unit is connected with a tachometer, since at high speed there is little time available to the driver in which to detect a person, and therefore the probability for a person to be overlooked is correspondingly greater. The decision unit may further be adapted to assess the visibility of a detected person in dependence of the type of road on which the vehicle is travelling. Such a detection may be based on a detection of steering maneuvers of the driver and may e.g. take account of the fact that low speed and frequent operation of the brakes points to the fact that the vehicle is travelling in a built-up area, whilst a constant movement in a straight line at high speed and small steering angles indicates a motorway. In the former case it is to be expected that people are frequently present in the vicinity of the vehicle and that it is possible for the driver to overlook one or two of them, whilst in the latter case there are normally no people in the vicinity of the vehicle but if this should be the case that the driver would notice them. The information, on which the assessment of the type of road driven over is based, can of course also be provided by a navigation system.
The people detection unit should further be adapted to estimate the distance of a detected person from the vehicle. As such, when deciding on the generation of a danger signal, note should be taken of the fact that a person far away from the driver is more likely to be overlooked than a person in the immediate vicinity of the vehicle. The people detection unit may include a camera, in particular an infrared camera. With such a people detection unit it is also convenient to assess the visibility of a detected person in dependence of the amount of detail in an image supplied by the camera, because in a vehicle environment which is rich in detail the probability of the driver overlooking a person is greater than in an environment with less detail.
The requirement set forth above is further met by a method for monitoring the environment of a vehicle including the steps of: (a) detecting the presence or absence of people in the vicinity of a vehicle; (b) assessing the visibility of the person for a driver of the vehicle when the presence of at least one person is detected; and (c) generating a danger signal if the visibility of the person drops below a limit value.
A subject of the present disclosure is also a computer program product which includes instructions which when being executed on a computer enable the same to function as a decision unit and/or a people detection unit of a vehicle environment monitoring system as described above or to execute the method described above. A further subject of the present disclosure is a computer-readable data carrier on which program instructions are recorded which enable a computer to operate in the above-described manner.
Further features and advantages of the present disclosure are revealed in the description below of exemplary embodiments with reference to the attached figures. This description and the attached figures also reveal features of the exemplary embodiments not mentioned in the claims. Such features may of course occur also in other than the specifically disclosed combinations. The fact that several such features are all mentioned in the same sentence or in another kind of textual context, therefore does not justify the conclusion that they may occur only in the specifically disclosed combination.